1. Field of the Invention
The present invention relates to an object detecting method for detecting a target object in an image, and a non-transitory computer-readable recording medium storing a program for causing a computer to perform an object detecting method.
2. Description of the Related Art
Technologies for detecting an object in an image taken by a camera, e.g., by processing information of the image, are being utilized in various fields of industry. For example, in the field of industrial robots, the information of an image imaged by a camera may be processed to detect an object in the image, and determine a positional error of the object in order to correct the position of an industrial robot. In the field of semiconductor manufacturing, in a size measuring step using length-measurement SEM (scanning electron microscopy) technology, an area around an alignment mark formed on a wafer may be taken by a camera, and the information of the image may be processed to detect the position of the alignment mark so that a position error of the wafer can be corrected.
Such image processing for object detection may involve pattern matching. For example, Japanese Laid-open Patent Publication No. 2008-234261 discusses a pattern matching technology whereby an image of an object is registered in advance, and an image including the object is obtained during an actual operation. Correlation values between the registered image and the image taken during the actual operation are calculated, and the presence or absence of the object or its position is detected based on the correlation values.
Pattern matching for object detection may involve moving a pre-registered standard pattern of a target object over an actual image including a determined pattern, and detecting a position in the image where the correspondence between the standard pattern and the determined pattern is large. Such an object detecting method based on pattern matching may involve the handling of large amounts of information and take a long time for object detection.